Development of Failure Probability Analysis Method for Concrete Piers of Multi-span Continuous Bridges using the Probabilistic Capacity Spectrum Method

When earthquakes occur, structures sustain damages. But it is impossible to estimate damages exactly which occur in the structures because of the uncertainty of materials and ground motions. Therefore, probabilistic methods for estimating damages of the structures have been suggested lately. In this study, probabilistic capacity spectrum method expanding established capacity spectrum method is suggested and this method is applied to calculation of the failure probability of the multi-span continuous bridges. While established capacity spectrum method doesn't reflect the uncertainty of materials and ground motions, probabilistic capacity spectrum method considers directly the uncertainty of the strength of the concrete in the capacity spectrum and the uncertainty of the ground motion in the demand spectrum. While the performance point appears one point using established capacity spectrum method, using probabilistic capacity spectrum method we obtain the probability of the performance point. Therefore, the failure probability of the bridges is calculated when earthquakes having specific return period occur. keywords : Multi-span Continuous Bridges, Reinforced Concrete Piers, Probabilistic Capacity Spectrum Method, Failure Probability, Performance Point ______________________________________________________________________________ Jae Shin CHOI, Graduate Student, Dept. of Civil, Urban & Geosystem Engineering , Seoul National University, Seoul, 151-742 Jae Kwan KIM, Professor, Dept. of Civil, Urban & Geosystem Engineering , Seoul National University, Seoul, 151-742